Safety catch for hydraulic jacks for automobiles

ABSTRACT

A rolling hydraulic auto jack has a shaft which telescopes to raise and lower an auto. The invention provides a metal channel or block which fits around the shaft to preclude a telescoping retraction thereof. This channel or block is a safety stop which keeps the jack from inadvertently lowering the auto, even if the hydraulic system fails.

Waited States Patent 1191 Lukas 1 Sept. 18, 1973 [54] SAFETY CATCH FORHYDRAULIC JACKS FOR AUTOMOBILES [76] Inventor: Paul Lukas, 3815 E.Layton Ave.,

' Cudahy, Wis. 53110 221 Filecl: Dec. 16, 1971 211 Appl. 110.; 208,595

[52] US. Cl. 254/8 R, 92/23 [5 1] Int. Cl 860p 1/48 [58] Flld of Search254/8 R, 93 R; 92/15, 23, 30

[56] References Cited UNITED STATES PATENTS 3,135,555 6/l964 Caskey92/23 2,998,224 8/196] Reisig 254/8R Primary Examiner-Othell M. SimpsonAssistant Examiner-Robert G. Watson Attorney-lrwin C. Alter et al.

57 1 ABSTRACT A ,rolling'hydraulic auto jack has a shaft whichtelescopes to raise and lower an auto. The invention provides a metalchannel or block which fits around the shaft to preclude a telescopingretraction thereof. This channel or block is a safety stop which keepsthe jack from inadvertently lowering the auto, even if the hydraulicsystem fails.

'5 Claims, 5 Drawing Figures PATENTED l 3|975 FIG. 2

INVENTOR AUL LUKAS M CUW ATTORNEYS 1 SAFETY (IATCH FOR HYDRAULIC JACKSFOR AUTOMOBILES The invention relates to safety catches for rollinghydraulic floor jacks, for automobiles.

Hydraulic jacks are often built on rollers so that they may be pushedunder an auto and then operated to raise it. Thereafter, it is necessaryto perform some act to insure against an inadvertent lowering of thejack if the hydraulic system fails. Often, this act is a placing of anobject, such as a cinder block, under an axle of the raised auto. That,or a similar act, insures the safety of a person crawling under theauto. However, it also takes time, and therefore is costly and wasteful.

Accordingly, an object of my invention, is to provide a device that maybe applied to a conventional hydraulic jack, to insure against a releaseof it with safety.

Another object of my invention is to provide a device of the characterdescribed, that may be easily applied to the conventional rollinghydraulic jack.

Still another object is to provide a device of the described type whichreleases the hydraulic jack, without requiring any additional mechanicalequipment or further modification of the jack.

Other and further objects of the invention will become more apparent asthe description proceeds, when taken in conjunction with the drawings,in which:

FIG. 1 is a perspective view of the assembled safety catch device,

FIG. 2 is a top or plan view of the assembled device of FIG. 1;

FIG. 3 is a side elevation view of the device as shown in FIG. 2;

FIG. 4 is a schematic view of the inventive safety catch for the jack,as applied to an automotive floor jack that is shown in phantom and in araised position; and

FIG. 5 is a similar view, as shown in FIG. 4, with the safety catch andthe jack in a released position.

Similar reference characters indicate corresponding parts and features,throughout the several views. More particularly, the character 10identifies a horizontal tubular or sleeve bearing, for lateralinstallation into the body of a conventional hydraulic automobile floorjack, shown generally at l l, in FIGS. 4 and 5. The tubular bearing isequipped with a pair of perpendicularly extending arms 12, which may beattached to the tube 10, at the joints 13, in any efficient manner, suchas by welding, for example. These arms 12 hingedlysupport a lJ-shapedchannel member 14 at a pair of pivot points 15, by means of pins or inany other convenient, and efficient manner.

A vertically disposed plate 17 is attached'to the tubular bearing 10 atpoint 18, as by weldingoThe plate 17 supportsa compression spring 19, bymeans of a bolt 20. The vertical plate 17 is here shown as having arelease cord, chain, rod, or the like, 21 attached at point 22.

The purpose and function of the device is shown in FIGS. 4 and 5. Thechannel 14(see FIG. 4), is pivoted on bearing 10A in shaft 10 and pinand 16 in pivot point 15 and placed into position when the jackcompresses the spring 19 and lifts the auto into a'raised position. Thejack includes a hydraulic cylinder 30, and telescoping shaft 31,connected to a linkage assembly 33 at 32. When the hydraulic fluid ispumped into cylinder 30, the shaft 31. extends to such linkage 32. Whenthe channel 14 is raised,it partly surrounds the shaft 31 and props thelinkage 33 against cylinder 30 to prevent retraction thereof. Thus, theauto will not lower if fluid leaks out of cylinder 30.

When the release. cord 21 is pulled as shown by the arrow (see FIG. 5),it pulls the plate 17 into an angularly downward position, therebylowering the channel 14, and releasing the pressure on the spring 19.The jack 11 may now be lowered as shown in FIG. 5, by releasing thehydraulic fluid from the cylinder since the linkage 33 and cylinder 30are no longer propped apart.

The safety catch device is simple in construction, and easy to apply tomost rolling hydraulic auto jacks. When the jack is raised, spring 19automatically applies the safety catch. By pulling the cord 21, the jackmay be released.

Although I have shown a specific and detailed construction of thedevice, many changes may be made in the various parts without effectingtheir operativeness. Therefore, I reserve the rights to make suchchanges as I may deem necessary or convenient. The claims should beconstrued to cover all equivalents which do not depart from the spiritof my invention.

I claim: a

1. A rolling auto jack,

said auto jack comprising:

a hydraulic cylinder,

a shaft telescopingly movable in said cylinder,

linkage means connected to the end of said shaft for translating shaftmotion into raised and lowered jack positions, i

a safety means to prevent retraction of said shaft into said cylinder inthe event of malfunctioning of said cylinder, 7

said safety means comprising a propping block,

said proppingblock having a propping position preventing retraction ofsaid shaft and a non-propping position enabling retraction of the shaft,

said propping block in the propping position being contiguous to saidshaft between said linkage means and said cylinder,

said propping block normally in the non-propping position removed fromsaid shaft when said shaft is in the retracted position, and springmeans for automatically forcing said block intothe propping positionresponsive to an extension of said shaft. 2. The catchof claim 1 andmeans for manually releasing said catch by moving it to a non-proppingpositIOI'l'. V i

3. A rolling auto jack, said jack comprising a hydraulic cylinder, 3 ashaft telescopingly moving in said cylinder, linkage means connected tothe end of said shaft for translating shaft motion to raised and loweredshaft positions, p a safety catch to prevent retraction of said shaftinto said cylinder, said safety catch comprising a propping blockfitting adjacent said shaft between said linkage means and saidcylinder, and said propping block comprising a U-shaped channel partlysurrounding said shaft when in said propping position. i a 4. The catchof claim 3 and a pair'of arms pivotally attached to said U-shapedchannel and rigidly attached to a tubular bearing fitting into the frameof said jack.

5. The catch .of claim 4 and a tab attached to said eras-11*

1. A rolling auto jack, said auto jack comprising: a hydraulic cylinder,a shaft telescopingly movable in said cylinder, linkage means connectedto the end of said shaft for translating shaft motion into raised andlowered jack positions, a safety means to prevent retraction of saidshaft into said cylinder in the event of malfunctioning of saidcylinder, said safety means comprising a propping block, said proppingblock having a propping position preventing retraction of said shaft anda non-propping position enabling retraction of the shaft, said proppingblock in the propping position being contiguous to said shaft betweensaid linkage means and said cylinder, said propping block normally inthe non-propping position removed from said shaft when said shaft is inthe retracted position, and spring means for automatically forcing saidblock into the propping position responsive to an extension of saidshaft.
 2. The catch of claim 1 and means for manually releasing saidcatch by moving it to a non-propping position.
 3. A rolling auto jack,said jack comprising a hydraulic cylinder, a shaft telescopingly movingin said cylinder, linkage means connected to the end of said shaft fortranslating shaft motion to raised and lowered shaft positions, a safetycatch to prevent retraction of said shaft into said cylinder, saidsafety catch comprising a propping block fitting adjacent said shaftbetween said linkage means and said cylinder, and said propping blockcomprising a U-shaped channel partly surrounding said shaft when in saidpropping position.
 4. The catch of claim 3 and a pair of arms pivotallyattached to said U-shaped channel and rigidly attached to a tubularbearing fitting into the frame of said jack.
 5. The catch of claim 4 anda tab attached to said bearing, and said release means comprises meansfor moving said tab to rotate said bearing and move said block.